From: Jiaxun Yang Date: Tue, 28 Feb 2023 11:33:04 +0000 (+0000) Subject: bpf, mips: Implement DADDI workarounds for JIT X-Git-Tag: v6.6.7~2736^2~413^2~35 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=bbefef2f07080cd502a93cb1c529e1c8a6c4ac8e;p=platform%2Fkernel%2Flinux-starfive.git bpf, mips: Implement DADDI workarounds for JIT For DADDI errata we just workaround by disable immediate operation for BPF_ADD / BPF_SUB to avoid generation of DADDIU. All other use cases in JIT won't cause overflow thus they are all safe. Signed-off-by: Jiaxun Yang Signed-off-by: Daniel Borkmann Reviewed-by: Philippe Mathieu-Daudé Acked-by: Johan Almbladh Link: https://lore.kernel.org/bpf/20230228113305.83751-2-jiaxun.yang@flygoat.com --- diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 15cb692..b89c4bf 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -64,7 +64,6 @@ config MIPS select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE select HAVE_EBPF_JIT if !CPU_MICROMIPS && \ - !CPU_DADDI_WORKAROUNDS && \ !CPU_R4000_WORKAROUNDS && \ !CPU_R4400_WORKAROUNDS select HAVE_EXIT_THREAD diff --git a/arch/mips/net/bpf_jit_comp.c b/arch/mips/net/bpf_jit_comp.c index b17130d..a40d926 100644 --- a/arch/mips/net/bpf_jit_comp.c +++ b/arch/mips/net/bpf_jit_comp.c @@ -218,9 +218,13 @@ bool valid_alu_i(u8 op, s32 imm) /* All legal eBPF values are valid */ return true; case BPF_ADD: + if (IS_ENABLED(CONFIG_CPU_DADDI_WORKAROUNDS)) + return false; /* imm must be 16 bits */ return imm >= -0x8000 && imm <= 0x7fff; case BPF_SUB: + if (IS_ENABLED(CONFIG_CPU_DADDI_WORKAROUNDS)) + return false; /* -imm must be 16 bits */ return imm >= -0x7fff && imm <= 0x8000; case BPF_AND: